Biogeography - International Baccalaureate Biology - Lecture Slides, Slides of Biology

Download Biogeography - International Baccalaureate Biology - Lecture Slides and more Slides Biology in PDF only on Docsity! Biogeography •mammals come in 3 forms: placental, monotremes, and marsupial •placental mammals are numerous world-wide except Australia, New Zealand •marsupials and monotremes are in Australia and New Zealand •Why? Docsity.com •As Pangea split 220 million years ago mammals were evolving •Australia split from the supercontinent early and it is believed that the ancestor to marsupials was found there •elsewhere they were outcompeted Docsity.com Docsity.com Evolution can be observed today in a number of instances: 1. Insecticide resistance •DDT was a lethal form of insecticide to all insects in 1950’s but today 225 species are resistant. One actually uses it for a food source. Docsity.com 2. Antibiotic resistance • a wonder drug of the 50’s it helped cure many ailments •because of over-prescription and abuse by patients many new mutated forms of bacteria are emerging that are antibiotic resistant Docsity.com